Rheumatology pearls

Nuclear Antigens:

Anti-Ro: seen in Sjogren's syndrome, SLE, congenital heart block

Anti-La: seen in Sjogren's syndrome

Anti-Jo 1: seen in polymyositis

Anti-SCL-70: seen in diffuse cutaneous systemic sclerosis

Anti-centromere: seen in limited cutaneous systemic sclerosis

Excretion of uric acid decreased with: 

Drugs like diuretics

Chronic kidney disease

Lead toxicity

Indications for allopurinol in patient with Gout:

2 or more attacks in 12 month period

Tophi

Renal disease

Uric acid renal stones

Prophylaxis if the patient is on cytotoxics or diuretics

Gout

Normal or low uric acid levels do not rule out gout

High percent of people with hyperuricemia do not have gout

Do not start allopurinol during acute gout flare because it can worsen an acute attack

Risk factors for Pseudogout are:

Hyperparathyroidism

Hypothyroidism

Hemochromatosis

Acromegaly

Low magnesium, low phosphate

Wilson's disease

  

Poor prognostic features in rheumatic arthritis are:

Positive rheumatoid factor (RF)

Poor functional status at presentation

Human leukocyte antigen (HLA) DR4

X-ray: early erosions (in less than 2 years)

Extra articular features e.g. Nodules

Females

Insidious onset

Anti cyclic citrullinated peptide (Anti-CCP) antibodies

Rheumatic arthritis and ischemic heart disease

Rheumatic arthritis carries a similar risk for ischemic heart disease (IHD) as type 2 diabetes mellitus (T2DM)

Proteus mirabilis and rheumatic arthritis

Proteus mirabilis urinary tract infections are the main triggering factor for rheumatic arthritis because of the presence of molecular mimicry and cross reactivity between these bacteria and rheumatic arthritis targeted tissue antigens through production of cytopathic auto antibodies.

Reactive Arthritis (Reiter's syndrome):

Reactive Arthritis is Human leukocyte antigen (HLA-B27) positive in about 80% of the patients. It called Reiter's syndrome, it has classic triad of urethritis, conjunctivitis and arthritis (the patient can't see, can't pee, can't bend the knee).

it is triggered by bacterial infection with Campylobacter, Chlamydia, Salmonella, Shigella, and Yersinia

Ankylosing spondylitis develop in up to 50% of Human leukocyte antigen (HLA B27) positive patients, and 90-95% of patients with ankylosing spondylitis have positive human leukocyte antigen (HLA-B27)

Ankylosing spondylitis:

7As

Apical fibrosis (CXR)

Anterior uveitis

Aortic regurgitation

Achilles tendonitis

AV node block

Amyloidosis

And cauda equina syndrome

X-ray of the sacro-iliac joints is the most useful investigation for diagnosis and monitoring patient with Ankylosing spondylitis

Systemic lupus erythematous (SLE):

Complement levels (C3, C4) are low during active disease, low C4 is early marker for disease activity

Systemic lupus erythematous (SLE) often becomes worse during pregnancy and the puerperium

The most common respiratory complication of Systemic lupus erythematous (SLE) is pleural effusions

Systemic lupus erythematous (SLE) can cause deforming arthritis but non erosive

Drugs that may cause drug induced Lupus:

Anti-epileptics: phenytoin

Chlorpromazine

Hydralazine

Isoniazid

Minocycline

Procainamide

The combination of pulmonary and renal involvement combined with a history of chronic sinusitis points towards a diagnosis of Wegener's granulomatosis

Behcet's Syndrome:

Behcet's Syndrome, has a classic triad of symptoms is oral ulcers, genital ulcers and anterior uveitis

Antiphospholipid Syndrome (Hughes syndrome) characterized by low platelets count with paradoxical rise in the activated partial thromboplastin time (APTT)

The trapeziometacarpal joint (base of thumb) is the most common site of hand osteoarthritis

Wegeners granulomatosis affects the upper respiratory tract and lungs in 90% of cases as it most commonly presents as rhinorrhea then nasal mucosal ulceration and cough, hemoptysis and pleuritic pain. Renal tissue is affected in 80% of cases, musculoskeletal system in 60%, gastrointestinal tract in about half of cases and the skin is less commonly involved with only 40% affected

  

Staph. Aureus is the most common organism to lead to septic arthritis

  

IgA nephropathy is the most common findings on a renal biopsy of a patient with ankylosing spondylitis who has hematuria and proteinuria

Knee and hip are the most affected joint in septic arthritis

Erythrocyte sedimentation rate (ESR) can be elevated in inflammation, infection, autoimmune disorders, anemia, end stage renal disease, females, increased age, obesity and some cancers (such as lymphoma and multiple myeloma)

Osteoarthritis of the hand:

Heberden's nodes: osteophytes causing enlargement of the distal interphalangeal (DIP) joint closest to the fingertips

Bouchard's nodes: osteophytes causing enlargement of the proximal interphalangeal (PIP) joints, it is less common than heberden's nodes

Causes of Erosive arthritis:

Rheumatoid arthritis

Psoriatic arthritis

Reactive arthritis (Reiter syndrome)

Ankylosing spondylitis

Gout

Hydroxyapatite crystal deposition disease (HADD)

Amyloidosis

Multicentric reticulo-histiocytosis

Infectious arthritis

Scleroderma

Malignancies Associated with dermatomyositis (DMM):

Breast

Lung

Colon

Ovarian

Sjögren’s syndrome

Sjögren’s syndrome is a risk factor of non-Hodgkin’s lymphoma

Mixed connective tissue disease (MCTD)

Only about 10% of cases will remain as MCTD for the rest of their lives

The other 90% evolved into SLE or scleroderma

Polyarteritis nodosa:

Polyarteritis nodosa is negative antineutrophil cytoplasmic antibodies (ANCA), and it is associate with hepatitis B in 5 – 10%

Giant cell arthritis

Treat on clinical suspicion with high dose prednisone 1 mg/kg in divided doses and don’t wait for investigation results because delay treatment may lead to blindness in about 25% of the cases